Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach

Mohammad Biabanifard,Arash Arsanjani,Mohammad Sadegh Abrishamian,Derek Abbott

doi:10.1109/access.2020.2986682

Abstract

In this paper, a simple, fast, and novel method for designing a tunable terahertz absorber with arbitrary central frequency and desired fractional bandwidth is presented. The proposed absorber consists of a single layer periodic array of graphene ribbons (PAGRs), placed a quarter wavelength from a metallic ground, separated by a dielectric material. An analytical circuit model of the terahertz absorber is used to obtain analytical expressions for the input impedance of the proposed device. Then, a simple expression for determining the value of capacitance and the resonance conditions of the RLC circuit is used to achieve a terahertz absorber with arbitrary central frequency and desired fractional bandwidth. The proposed method is applicable for the design of both narrowband and broadband absorbers, with only one layer of graphene ribbons. Also, the presented method is applicable for designing ultra-wideband absorbers using multiple layered PAGRs. Full-wave numerical simulation is performed to verify the accuracy and validity of the presented method. Excellent performance of the proposed method in terms of computation time and memory resource and providing the desired terahertz absorber characteristics shows that our method is promising as a design approach for sensing, imaging and filtering applications.

Highlights

Terahertz technology, a significant step in the realization of high-speed devices, is not yet fully developed and the capabilities of terahertz waves are not fully realized
Five graphene-based terahertz absorbers with only one layer of periodic array of graphene ribbons (PAGRs) and one ultra-wideband absorber with two graphene-layer is designed as numerical examples to validate the proposed method; where the designed parameters are given in Table 2 and Table 3, respectively
Biabanifard et al.: Tunable Terahertz Graphene-Based Absorber Design Method Based on a Circuit Model Approach TABLE 2

Summary

Introduction

A significant step in the realization of high-speed devices, is not yet fully developed and the capabilities of terahertz waves are not fully realized. The terahertz spectra (roughly from 0.1 to 10 THz), which is a bridge between microwave and infrared frequencies, is referred to as the terahertz gap. This region of the spectra is of significant interest for high-frequency applications [1]–[6]. Sensing, biosensing, imaging, indoor communications, and medical applications are among the applications that are currently being studied [1]–[6]. The use of metamaterials, which are artificial sub-wavelength composite materials, has facilitated the realization of terahertz devices for a number of applications. Because of the exceptional physical and electromagnetic properties of graphene, one layer of carbon atoms

Methods

Results

Conclusion